Multiple queue manager instances

A multi-instance queue manager is resilient because it uses a standby queue manager instance to restore queue manager availability after failure.

Replicating queue manager instances is a very effective way to improve the availability of queue manager processes. Using a simple availability model, purely for illustration: if the reliability of one instance of a queue manager is 99% (over one year, cumulative downtime is 3.65 days) then adding another instance of the queue manager increases the availability to 99.99% (over one year, cumulative downtime of about an hour).

This is too simple a model to give you practical numeric estimates of availability. To model availability realistically, you need to collect statistics for the mean time between failures (MTBF) and the mean time to repair (MTTR), and the probability distribution of time between failures and of repair times.

The term, multi-instance queue manager, refers to the combination of active and standby instances of the queue manager that share the queue manager data and logs. Multi-instance queue managers protect you against the failure of queue manager processes by having one instance of the queue manager active on one server, and another instance of the queue manager on standby on another server, ready to take over automatically should the active instance fail.